In this post, I will show the steps on how to bare-root repot a nursery stock satsuki azalea into a bonsai or training pot. I live in Zone 9, mid March to end of April are the best times to do bare-root repotting for azalea.
This “wakebisu” satsuki azalea was repotted on March 10, 2014. It was in a black plastic pot and the soil had broken down and became water-logged.
Use a strong water jet to wash out the old soil, and use a pair of tweezers to unentangle and tease the roots outwards. Be careful to keep as much fine roots as possible. Repeat this process until all the old soils are completely removed. This is the most time consuming step.
Inspect the inner root ball; this plant has some rotted and unhealthy black roots which must be removed. Seal the wounds with cut-paste. I use Top-Jin, an orange color cut-paste, which contains fungicide to prevent the wounds from rotting.
Keep as many fine roots as possible, and plant the tree in 100% kanuma. This tree is 21″ tall and has a trunk caliper of close to 2″, so I used 100% medium size kanuma. After potting, spread some sphagnum moss on top of the soil to help retaining moisture while the tree recovers.
In addition to tie wires in the pot, I secure the tree with ropes to prevent movements while new roots are growing. I also cut away unwanted branches and drastically reduce their lengths. At this time of the year, branches can be fully cut back without leaving any leaf on them, but it is a good idea to keep at least a pair of leaves wherever possible. Since the root mass has been drastically reduced, it is important to cut back branches and remove most of the leaves to match the reduced root mass acordingly.
March 27, 2014. New buds had popped out all over the tree.
February 26, 2015. The tree had grown vigorously a year after bare-root potting.
Flowers on the repotted tree on May 7, 2015.
I plant my satsuki azaleas in 100% kanuma because they have high water retention capacity and are fast draining. They are also acidic which azaleas love.
Bare root repotting may look scary. Try it with a small inexpensive plant and see how it works, and figure out the nuances before going to your more expensive tree. Do this in early spring when temperature has warmed up, when there is no danger of frost, when branches begin to push out new growths, and when there are least one to two months of good spring weather for the tree to recover before summer heat sets in.